<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<title></title>
	</head>
	
	<body>
		
	</body>
	
	<script>
		var num = "abxxxxx123abc";
		
		var n = parseInt(num);
		
		console.log(n);  // NaN   Not a Number
		
		var m = parseInt("yt");
		
		console.log(NaN == NaN); //NaN 不等于 NaN
		
		
		
	</script>
	
	
</html>



